After the trial, the witness, believed to be a firefighter, apparently told Bronx prosecutors about the juror’s electronic message to him. Prosecutors alerted the trial judge and defense attorneys.

Gerald Shargel, a prominent Manhattan defense attorney, said the juror’s contact with the witness “is so beyond the pale that . . . the appearance of impropriety is manifest. It calls the verdict into question.”

Eric Freedman, a Hofstra University constitutional law professor, agreed. “A juror is supposed to enter a trial impartially and preserve that impartiality throughout the testimony,” Freedman said.

Firefighters Brendan Cawley, Jeffery Cool, Joseph DiBernardo and Eugene Stolowski – all injured in the fire – testified during the trial, which ended in February.

Cawley would not say whether the juror had contacted him. Cool said the juror did not contact him. DiBernardo and Stolowski could not be reached for comment.

“I know about the whole situation with Facebook,” Cawley said in a telephone conversation. “I’ve been warned and told not to discuss it.”